Apparatus, system and method of adjusting transmission intervals for discovery frames

ABSTRACT

Some demonstrative embodiments include apparatuses, systems and/or methods of adjusting transmission intervals for discovery frames. For example, an apparatus may include a wireless communication unit to communicate over a wireless communication medium according to a discovery scheme including a plurality of contention-based discovery windows, the wireless communication unit is to select a discovery window according to a transmission interval, to schedule transmission of a discovery frame for the discovery window, and to adjust the transmission interval based on whether or not the wireless communication medium is observed to be busy during a predefined time period of the discovery window.

CROSS REFERENCE

This application claims the benefit of and priority from U.S.Provisional Patent application No. 61/819, 736 entitled “Backofftechniques for group addressed frames enabling low power discovery”,filed May 6, 2013, the entire disclosure of which is incorporated hereinby reference.

TECHNICAL FIELD

Embodiments described herein generally relate to adjusting transmissionintervals for discovery frames.

BACKGROUND

In some wireless communication networks, communication may be performedduring discovery windows (DWs).

Stations may be allowed to transmit a discovery frame during a DW, inorder to enable the stations to discover other devices or services thatare running on the other devices.

Transmissions may be preformed during the DW based on a contentionmechanism.

A plurality of stations may attempt to transmit discovery frames duringthe DWs, which may be relatively short. These attempts may result in arelatively high level of congestion within the network. The congestionmay result in failure to transmit the discovery frames.

BRIEF DESCRIPTION OF THE DRAWINGS

For simplicity and clarity of illustration, elements shown in thefigures have not necessarily been drawn to scale. For example, thedimensions of some of the elements may be exaggerated relative to otherelements for clarity of presentation. Furthermore, reference numeralsmay be repeated among the figures to indicate corresponding or analogouselements. The figures are listed below.

FIG. 1 is a schematic block diagram illustration of a system, inaccordance with some demonstrative embodiments.

FIG. 2 is a schematic illustration of a discovery scheme including aplurality of contention-based discovery windows, in accordance with somedemonstrative embodiments.

FIG. 3 is a schematic flow-chart illustration of a method of adjustingtransmission intervals for discovery frames, in accordance with somedemonstrative embodiments.

FIG. 4 is a schematic illustration of a product, in accordance with somedemonstrative embodiments.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of some embodiments.However, it will be understood by persons of ordinary skill in the artthat some embodiments may be practiced without these specific details.In other instances, well-known methods, procedures, components, unitsand/or circuits have not been described in detail so as not to obscurethe discussion.

Discussions herein utilizing terms such as, for example, “processing”,“computing”, “calculating”, “determining”, “establishing”, “analyzing”,“checking”, or the like, may refer to operation(s) and/or process(es) ofa computer, a computing platform, a computing system, or otherelectronic computing device, that manipulate and/or transform datarepresented as physical (e.g., electronic) quantities within thecomputer's registers and/or memories into other data similarlyrepresented as physical quantities within the computer's registersand/or memories or other information storage medium that may storeinstructions to perform operations and/or processes.

The terms “plurality” and “a plurality”, as used herein, include, forexample, “multiple” or “two or more”. For example, “a plurality ofitems” includes two or more items.

References to “one embodiment”, “an embodiment”, “demonstrativeembodiment”, “various embodiments” etc., indicate that the embodiment(s)so described may include a particular feature, structure, orcharacteristic, but not every embodiment necessarily includes theparticular feature, structure, or characteristic. Further, repeated useof the phrase “in one embodiment” does not necessarily refer to the sameembodiment, although it may.

As used herein, unless otherwise specified the use of the ordinaladjectives “first,” “second,” “third,” etc., to describe a commonobject, merely indicate that different instances of like objects arebeing referred to, and are not intended to imply that the objects sodescribed must be in a given sequence, either temporally, spatially, inranking, or in any other manner.

Some embodiments may be used in conjunction with various devices andsystems, for example, a Personal Computer (PC), a desktop computer, amobile computer, a laptop computer, a notebook computer, a tabletcomputer, a server computer, a handheld computer, a handheld device, aPersonal Digital Assistant (PDA) device, a handheld PDA device, anon-board device, an off-board device, a hybrid device, a vehiculardevice, a non-vehicular device, a mobile or portable device, a consumerdevice, a non-mobile or non-portable device, a wireless communicationstation, a wireless communication device, a wireless Access Point (AP),a wired or wireless router, a wired or wireless modem, a video device,an audio device, an audio-video (A/V) device, a wired or wirelessnetwork, a wireless area network, a Wireless Video Area Network (WVAN),a Local Area Network (LAN), a Wireless LAN (WLAN), a Personal AreaNetwork (PAN), a Wireless PAN (WPAN), and the like.

Some embodiments may be used in conjunction with devices and/or networksoperating in accordance with existing Wireless-Gigabit-Alliance (WGA)specifications (Wireless Gigabit Alliance, Inc WiGig MAC and PHYSpecification Version 1.1, April 2011, Final specification) and/orfuture versions and/or derivatives thereof, devices and/or networksoperating in accordance with existing IEEE 802.11 standards (IEEE802.11-2012, IEEE Standard for Information technology—Telecommunicationsand information exchange between systems Local and metropolitan areanetworks—Specific requirements Part 11: Wireless LAN Medium AccessControl (MAC) and Physical Layer (PHY) Specifications, Mar. 29, 2012;IEEE802.11 task group ac (TGac) (“IEEE802.11-09/0308r12—TGac ChannelModel Addendum Document”); IEEE 802.11 task group ad (TGad) (IEEEP802.11ad-2012, IEEE Standard for InformationTechnology—Telecommunications and Information Exchange BetweenSystems—Local and Metropolitan Area Networks—Specific Requirements—Part11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)Specifications—Amendment 3: Enhancements for Very High Throughput in the60 GHz Band, 28 December, 2012)) and/or future versions and/orderivatives thereof, devices and/or networks operating in accordancewith existing WirelessHD™ specifications, and/or future versions and/orderivatives thereof, devices and/or networks operating in accordancewith existing and/or Wireless Fidelity (WiFi) Alliance (WFA)Peer-to-Peer (P2P) specifications (WiFi P2P) technical specification,version 1.3, 2012) and/or future versions and/or derivatives thereof,units and/or devices which are part of the above networks, and the like.

Some embodiments may be used in conjunction with one way and/or two-wayradio communication systems, cellular radio-telephone communicationsystems, a mobile phone, a cellular telephone, a wireless telephone, aPersonal Communication Systems (PCS) device, a PDA device whichincorporates a wireless communication device, a mobile or portableGlobal Positioning System (GPS) device, a device which incorporates aGPS receiver or transceiver or chip, a device which incorporates an RFIDelement or chip, a Multiple Input Multiple Output (MIMO) transceiver ordevice, a Single Input Multiple Output (SIMO) transceiver or device, aMultiple Input Single Output (MISO) transceiver or device, a devicehaving one or more internal antennas and/or external antennas, DigitalVideo Broadcast (DVB) devices or systems, multi-standard radio devicesor systems, a wired or wireless handheld device, e.g., a Smartphone, aWireless Application Protocol (WAP) device, or the like.

Some embodiments may be used in conjunction with one or more types ofwireless communication signals and/or systems, for example, RadioFrequency (RF), Infra Red (IR), Frequency-Division Multiplexing (FDM),Orthogonal FDM (OFDM), Time-Division Multiplexing (TDM), Time-DivisionMultiple Access (TDMA), Extended TDMA (E-TDMA), General Packet RadioService (GPRS), extended GPRS, Code-Division Multiple Access (CDMA),Wideband CDMA (WCDMA), CDMA 2000, single-carrier CDMA, multi-carrierCDMA, Multi-Carrier Modulation (MDM), Discrete Multi-Tone (DMT),Bluetooth®, Global Positioning System (GPS), Wi-Fi, Wi-Max, ZigBee™,Ultra-Wideband (UWB), Global System for Mobile communication (GSM), 2G,2.5G, 3G, 3.5G, 4G, Fifth Generation (5G) mobile networks, 3GPP, LongTerm Evolution (LTE), LTE advanced, Enhanced Data rates for GSMEvolution (EDGE), or the like. Other embodiments may be used in variousother devices, systems and/or networks.

The term “wireless device”, as used herein, includes, for example, adevice capable of wireless communication, a communication device capableof wireless communication, a communication station capable of wirelesscommunication, a portable or non-portable device capable of wirelesscommunication, or the like. In some demonstrative embodiments, awireless device may be or may include a peripheral that is integratedwith a computer, or a peripheral that is attached to a computer. In somedemonstrative embodiments, the term “wireless device” may optionallyinclude a wireless service.

The term “communicating” as used herein with respect to a wirelesscommunication signal includes transmitting the wireless communicationsignal and/or receiving the wireless communication signal. For example,a wireless communication unit, which is capable of communicating awireless communication signal, may include a wireless transmitter totransmit the wireless communication signal to at least one otherwireless communication unit, and/or a wireless communication receiver toreceive the wireless communication signal from at least one otherwireless communication unit.

Some demonstrative embodiments may be used in conjunction with suitablelimited-range or short-range wireless communication networks, forexample, a wireless area network, a “piconet”, a WPAN, a WVAN and thelike. Other embodiments may be used in conjunction with any othersuitable wireless communication network.

Some demonstrative embodiments may be used in conjunction with awireless communication network communicating over a frequency band of 60GHz. However, other embodiments may be implemented utilizing any othersuitable wireless communication frequency bands, for example, anExtremely High Frequency (EHF) band (the millimeter wave (mmWave)frequency band), e.g., a frequency band within the frequency band ofbetween 20 Ghz and 300 GHZ, a WLAN frequency band, a WPAN frequencyband, a frequency band according to the WGA specification, and the like.

The term “antenna”, as used herein, may include any suitableconfiguration, structure and/or arrangement of one or more antennaelements, components, units, assemblies and/or arrays. In someembodiments, the antenna may implement transmit and receivefunctionalities using separate transmit and receive antenna elements. Insome embodiments, the antenna may implement transmit and receivefunctionalities using common and/or integrated transmit/receiveelements. The antenna may include, for example, a phased array antenna,a single element antenna, a set of switched beam antennas, and/or thelike.

The term “station” (STA), as used herein, may include any logical entitythat is a singly addressable instance of a medium access control (MAC)and a physical layer (PHY) interface to a wireless medium (WM).

The phrase “access point” (AP), as used herein, may include an entitythat contains one station (STA) and provides access to distributionservices, via the WM for associated STAs.

The phrase “non-access-point (non-AP) station (STA)”, as used herein,may relate to a STA that is not contained within an AP.

The phrase “peer to peer (PTP or P2P) communication”, as used herein,may relate to device-to-device communication over a wireless link(“peer-to-peer link”) between a pair of devices. The P2P communicationmay include, for example, wireless communication over a direct linkwithin a QoS basic service set (BSS), a tunneled direct-link setup(TDLS) link, a STA-to-STA communication in an independent basic serviceset (IBSS), or the like.

Reference is now made to FIG. 1, which schematically illustrates a blockdiagram of a system 100, in accordance with some demonstrativeembodiments.

As shown in FIG. 1, in some demonstrative embodiments system 100 mayinclude a wireless communication network including one or more wirelesscommunication devices, e.g., wireless communication devices 102, 104,106 and/or 108, capable of communicating content, data, informationand/or signals over a wireless communication medium 103, for example, aradio channel, an IR channel, a RF channel, a Wireless Fidelity (WiFi)channel, and the like. One or more elements of system 100 may optionallybe capable of communicating over any suitable wired communication links.

In some demonstrative embodiments, wireless communication devices 102,104 106 and/or 108 may include, for example, a PC, a desktop computer, amobile computer, a laptop computer, a notebook computer, a tabletcomputer, a server computer, a handheld computer, a handheld device, aPDA device, a handheld PDA device, an on-board device, an off-boarddevice, a hybrid device (e.g., combining cellular phone functionalitieswith PDA device functionalities), a consumer device, a vehicular device,a non-vehicular device, a mobile or portable device, a non-mobile ornon-portable device, a mobile phone, a cellular telephone, a PCS device,a PDA device which incorporates a wireless communication device, amobile or portable GPS device, a DVB device, a relatively smallcomputing device, a non-desktop computer, a “Carry Small Live Large”(CSLL) device, an Ultra Mobile Device (UMD), an Ultra Mobile PC (UMPC),a Mobile Internet Device (MID), an “Origami” device or computing device,a device that supports Dynamically Composable Computing (DCC), acontext-aware device, a video device, an audio device, an A/V device, aSet-Top-Box (STB), a Blu-ray disc (BD) player, a BD recorder, a DigitalVideo Disc (DVD) player, a High Definition (HD) DVD player, a DVDrecorder, a HD DVD recorder, a Personal Video Recorder (PVR), abroadcast HD receiver, a video source, an audio source, a video sink, anaudio sink, a stereo tuner, a broadcast radio receiver, a flat paneldisplay, a Personal Media Player (PMP), a digital video camera (DVC), adigital audio player, a speaker, an audio receiver, an audio amplifier,a gaming device, a data source, a data sink, a Digital Still camera(DSC), a media player, a Smartphone, a television, a music player, orthe like.

In some demonstrative embodiments, wireless communication devices 102,104, 106 and/or 108 may include wireless communication units, to performwireless communication between wireless communication devices 102, 104,106 and/or 108 and/or with one or more other wireless communicationdevices. For example, device 102 may include a wireless communicationunit 110 and device 104 may include a wireless communication unit 120,e.g., as described below.

Wireless communication devices 102, 104, 106 and/or 108 may alsoinclude, for example, one or more of a processor 191, an input unit 192,an output unit 193, a memory unit 194, and a storage unit 195. Wirelesscommunication devices 102, 104, 106 and/or 108 may optionally includeother suitable hardware components and/or software components. In somedemonstrative embodiments, some or all of the components of one or moreof wireless communication devices 102, 104, 106 and/or 108 may beenclosed in a common housing or packaging, and may be interconnected oroperably associated using one or more wired or wireless links. In otherembodiments, components of one or more of wireless communication devices102, 104, 106 and/or 108 may be distributed among multiple or separatedevices.

Processor 191 includes, for example, a Central Processing Unit (CPU), aDigital Signal Processor (DSP), one or more processor cores, asingle-core processor, a dual-core processor, a multiple-core processor,a microprocessor, a host processor, a controller, a plurality ofprocessors or controllers, a chip, a microchip, one or more circuits,circuitry, a logic unit, an Integrated Circuit (IC), anApplication-Specific IC (ASIC), or any other suitable multi-purpose orspecific processor or controller. Processor 191 executes instructions,for example, of an Operating System (OS) of wireless communicationdevices 102, 104, 106 and/or 108 and/or of one or more suitableapplications.

Input unit 192 includes, for example, a keyboard, a keypad, a mouse, atouch-screen, a touch-pad, a track-ball, a stylus, a microphone or,other suitable pointing device or input device. Output unit 193includes, for example, a monitor, a screen, a touch-screen, a flat paneldisplay, a Cathode Ray Tube (CRT) display unit, a Liquid Crystal Display(LCD) display unit, a plasma display unit, one or more audio speakers orearphones, or other suitable output devices.

Memory unit 194 includes, for example, a Random Access Memory (RAM), aRead Only Memory (ROM), a Dynamic RAM (DRAM), a Synchronous DRAM(SD-RAM), a flash memory, a volatile memory, a non-volatile memory, acache memory, a buffer, a short term memory unit, a long term memoryunit, or other suitable memory units. Storage unit 195 includes, forexample, a hard disk drive, a floppy disk drive, a Compact Disk (CD)drive, a CD-ROM drive, a DVD drive, or other suitable removable ornon-removable storage units. Memory unit 194 and/or storage unit 195,for example, may store data processed by wireless communication devices102, 104, 106 and/or 108.

In some demonstrative embodiments, wireless medium 103 may include, forexample, a Radio Frequency (RF) channel, a WiFi channel, a Bluetoothchannel, a cellular channel, a Global Navigation Satellite System (GNSS)Channel, a Near Field Communication (NFC) channel, a Hybrid DigitalRadio (HDR) channel, a Frequency Modulation (FM) channel, and the like.

In some demonstrative embodiments, wireless communication medium 103 mayinclude a wireless communication channel over a 2.4 Gigahertz (GHz)frequency band, or a 5 GHz frequency band.

In other embodiments, wireless communication medium 103 may include anyother channel, e.g., a wireless communication channel over a 60Gigahertz (GHz) frequency band, or any other frequency band.

In some demonstrative embodiments, wireless communication units 110 and120 may include, or may be associated with, one or more antennas 107 and109, respectively. Antennas 107 and 109 may include any type of antennassuitable for transmitting and/or receiving wireless communicationsignals, blocks, frames, transmission streams, packets, messages and/ordata. For example, antennas 107 and 109 may include any suitableconfiguration, structure and/or arrangement of one or more antennaelements, components, units, assemblies and/or arrays. Antennas 107 and109 may include, for example, antennas suitable for directionalcommunication. For example, antennas 107 and 109 may include a phasedarray antenna, a single element antenna, a set of switched beamantennas, and/or the like. In some embodiments, antennas 107 and 109 mayimplement transmit and receive functionalities using separate transmitand receive antenna elements. In some embodiments, antennas 107 and 109may implement transmit and receive functionalities using common and/orintegrated transmit/receive elements.

In some demonstrative embodiments, wireless communication units 110and/or 120 include, for example, one or more radios 114, e.g., includingone or more wireless transmitters, receivers and/or transceivers able tosend and/or receive wireless communication signals, RF signals, frames,blocks, transmission streams, packets, messages, data items, and/ordata. For example, wireless communication units 110 and/or 120 mayinclude or may be implemented as part of a wireless Network InterfaceCard (NIC), and the like.

In some demonstrative embodiments, wireless communication devices 102,104, 106 and/or 108 may form a wireless local area network (WLAN).

In some demonstrative embodiments, wireless communication medium 103 mayinclude a wireless communication link over the mmWave band, e.g., theDMG band.

In some demonstrative embodiments, devices 102, 104, 106 and/or 108 mayperform the functionality of mmWave STAs, e.g., DMG stations (“DMGSTA”). For example, devices 102, 104, 106 and/or may be configured tocommunicate over the DMG band.

In some demonstrative embodiments, wireless communication medium 103 mayinclude a wireless gigabit (WiGig) link. For example, wirelesscommunication medium 103 may include a wireless beamformed link over the60 GHZ frequency band.

In some demonstrative embodiments, wireless communication devices 102,104, 106 and/or 108 may form a WiFi network.

In some demonstrative embodiments, wireless communication medium 103 mayinclude a direct link, e.g., a P2P link, for example, to enable directcommunication between device 102 and devices 104, 106 and/or 108.

In some demonstrative embodiments, wireless communication devices 102,104, 106 and/or 108 may perform the functionality of WFA P2P devices.For example, device 102 may perform the functionality of a P2P groupowner, and devices 104, 106 and/or 108 may perform the functionality ofa P2P client device.

In some demonstrative embodiments, wireless communication devices 102,104, 106 and/or 108 may form a WiFi NAN network.

In some demonstrative embodiments, wireless communication devices 102,104, 106 and/or 108 may form a neighbor awareness networking (NAN)network. For example, devices 102, 104, 106 and/or 108 may include NANdevices, which may share a common set of NAN parameters, e.g., includinga common time period between consecutive discovery windows (DWs), e.g.,as described below.

In some demonstrative embodiments, wireless communication unit 110 mayperform the functionality of a NAN device capable of discovering otherNAN devices according to a discovery scheme.

In other embodiments, wireless communication devices 102, 104, 106and/or 108 may form any other network.

In other embodiments, wireless communication devices 102, 104, 106and/or 108 may perform the functionality of any other wirelesscommunication devices.

In some demonstrative embodiments, one or more of devices 102, 104, 106and/or 108 may perform a discovery procedure, for example, to discovereach other and/or to establish a directional and/or high throughputwireless communication link.

In some demonstrative embodiments, devices 102, 104, 106 and/or 108 maytransmit discovery frames according to a discovery scheme including aplurality of discovery windows.

In some demonstrative embodiments, devices 102, 104, 106 and/or 108 maycommunicate during a discovery window according to a contentionmechanism. For example, devices 102, 104, 106 and/or 108 may checkwhether or not a channel is unoccupied prior to an attempt to transmit adiscovery frame during the discovery window.

In some demonstrative embodiments, a device of devices 102, 104, 106and/or 108, e.g., device 102, may not transmit the discovery frameduring the DW, e.g., if the channel is occupied.

In some demonstrative embodiments, device 102 may transmit the discoveryframe during the DW, e.g., if the channel is unoccupied.

In some embodiments, the discovery frame may be transmitted as a groupaddressed, e.g., broadcast or multicast, discovery frame. In otherembodiments, the discovery frame may be transmitted as any other frame.

In some demonstrative embodiments, the discovery frame may not requirean acknowledgement frame. Therefore, a transmitter of the discoveryframe may not backoff a transmission of the discovery frame.

In some demonstrative embodiments, the discovery frame transmitted bydevice 102 during the DW may enable other devices or services that arerunning on other devices to discover the device.

In some demonstrative embodiments, the DW may be relatively short.

In some demonstrative embodiments, a congestion of wirelesscommunication medium 103 during a DW may be related to a duration of theDW and/or a number of devices in the network attempting a transmissionduring the DW. For example, the congestion may increase if the durationof the DW decreases and/or if the number of devices attempting totransmit discovery frames increases.

In some demonstrative embodiments, the congestion may result in failureto transmit the discovery frame.

In some demonstrative embodiments, an increased level of congestion overwireless communication medium 103 may result in an increased powerconsumption of device 102, e.g., since a number of attempts by device102 to transmit the discovery frame may increase.

In some demonstrative embodiments, spreading the transmissions ofdiscovery frames across multiple discovery windows and/or increasing thesize of the discovery windows may mitigate the congestion in thediscovery windows. However, spreading the transmissions of the discoveryframes and/or increasing the size of the DWs may require estimating thenumber of devices in the network.

In some demonstrative embodiments, estimating the number of devices inthe network may be difficult, e.g., since each device may see adifferent number of devices around it.

In some demonstrative embodiments, collisions between discovery frameswithin a DW may be mitigated, for example, even without estimating thenumber of devices, e.g., as described in detail below.

In some demonstrative embodiments, the success or failure of device 102to transmit a discovery frame during a predefined time period of thediscovery window may indicate a level of congestion of medium 103.

In some demonstrative embodiments, the ability of device 102 to transmita discovery frame before the end of the discovery window may indicatethat medium 103 is not highly congested.

In some demonstrative embodiments, the probability that device 102 maynot be able to transmit the discovery frame during the discovery windowmay increase, e.g., if medium 103 is observed to be busy during apredefined time period of the discovery window.

In some demonstrative embodiments, wireless communication unit 110 maybe configured to schedule transmissions of discovery frames based on theobservation of whether or not the medium is busy during the DWs, e.g.,as described below.

In some demonstrative embodiments, wireless communication unit 110 maytransmit the discovery frame during a selected discovery windowaccording to a transmission interval (TI), e.g., as described below.

In some demonstrative embodiments, wireless communication unit 110 mayschedule the transmission of the discovery frame for the discoverywindow, e.g., as described below.

In some demonstrative embodiments, wireless communication unit 110 mayadjust the transmission interval based on whether or not wirelesscommunication medium 103 is observed to be busy during a predefined timeperiod of the discovery window, e.g., as described in detail below.

In some demonstrative embodiments, wireless communication unit 110 mayincrease the TI, e.g., if wireless communication medium 103 is observedto be congested during the predefined time period of the discoverywindow.

In other demonstrative embodiments, wireless communication unit 110 maydecrease the TI, e.g., if wireless communication medium 103 is notobserved to be congested during the predefined time period of thediscovery window.

In some demonstrative embodiments, the predefined time period may berelated to a sensitivity of the TI to congestion. For example, a firsttime period may result in an adjustment of the TI, e.g., when wirelesscommunication medium 103 has at least a first congestion level; and asecond time period, e.g., shorter than the first time period, may resultin an adjustment of the TI, e.g., when wireless communication medium 103has at least a second congestion level, e.g., lesser than the firstcongestion level.

In some demonstrative embodiments, the predefined time period mayinclude a time period beginning at a start time of a DW, e.g., an n-thDW, and ending within the DW. For example, the predefined time period,denoted T, may be defined, e.g., as follows:

T=n-th DW start time+c×length of DW  (1)

wherein c denotes a predefined value, for example, 0<c<1, e.g., c=0.75or any other value.

In other embodiments, the predefined time period may include an entiretyof the DW, e.g., if c=1.

In some demonstrative embodiments, based on the transmission interval,wireless communication unit 110 may determine a number of discoverywindows between successive attempts to transmit the discovery frame, andselect the discovery window according to the number of discoverywindows, e.g., as described below.

In some demonstrative embodiments, wireless communication unit 110 mayselect the number of discovery windows between a minimal transmissioninterval and the transmission interval, e.g., as described below.

In some demonstrative embodiments, the transmission interval may includea Service Discovery frame transmission window (M).

In some demonstrative embodiments, device 102 may maintain the value ofTW and a minimal TW value, denoted TW_(min). In one example, TW_(min)=1,or any other value.

In some demonstrative embodiments, wireless communication unit 110 mayselect, e.g., randomly, a number, denoted n, between the minimaltransmission interval and the transmission interval, and may scheduletransmission of the discovery frame during an n-th discovery window,wherein n=0 denotes a current discovery window, e.g., as describedbelow.

In some demonstrative embodiments, wireless communication unit 110 mayadjust the transmission interval based on whether or not wirelesscommunication medium 103 is observed to be busy during the predefinedtime period of the discovery window, e.g., as described in detail below.

In some demonstrative embodiments, wireless communication unit 110 mayincrease the transmission interval, e.g., if the medium is observed tobe busy during the predefined time period. For example, the TI may beincreased, e.g., if device 102 cannot transmit the discovery frameduring the predefined time period in the n-th DW.

In some demonstrative embodiments, wireless communication unit 110 mayincrease the TI, for example, if wireless communication unit 110observes medium 103 is busy for more than the time period T. Forexample, wireless communication unit 110 may increase the value of TW,e.g., as follows:

TW=TW+a  (2)

wherein a denotes a predefined value. For example, a may include aconstant value, e.g., a=2, or any other value.

In some demonstrative embodiments, wireless communication unit 110 maydecrease the transmission interval, for example if medium 103 is notobserved to be busy for the predefined time period. For example, the TImay be decreased, e.g., if device 102 can transmit the discovery frameduring the predefined time period of the n-th DW.

In some demonstrative embodiments, wireless communication unit 110 maydecrease the TI, for example, if wireless communication unit 110observes medium 103 is not busy for more than the time period T. Forexample wireless communication unit 110 may decrease the value of TW,e.g., as follows:

TW=max{TW _(min),(TW−b)}  (3)

wherein b denotes a predefined value. For example, b may include aconstant value, e.g., b=1, or any other value.

In some demonstrative embodiments, wireless communication unit 110 maytransmit the discovery frame according to any other discovery scheme,e.g., as described below.

In some demonstrative embodiments, wireless communication unit 110 mayselect an i-th TI, denoted TI_(i), for the transmission of the discoveryframe. For example, wireless communication unit 110 may initialize thevalue of TI to a minimal predefined value, denoted Nmin, e.g., TI₁=Nmin.

In some demonstrative embodiments, wireless communication unit 110 mayselect a DW, for example, a DW separated by TI_(i) DWs from a currentDW.

In some demonstrative embodiments, wireless communication unit 110 mayattempt to transmit the discovery frame within the selected DW.

In some demonstrative embodiments, wireless communication unit 110 mayadjust the TI based on whether or not wireless communication medium 103is observed to be busy during the predefined time period of the DW.

In some demonstrative embodiments, wireless communication unit 110 maydecrease the selected transmission interval, e.g., if device 102 is ableto transmit the discovery frame before the end of the selected DW.

In some demonstrative embodiments, wireless communication unit 110 maydecrease the TI by determining a next TI, denoted TI_(i+1), to be usedfor selecting a next DW, e.g., as follows:

TI _(i+1)=max(Nmin,TI _(i)−1)  (4)

In another example, the successive TI may be determined by decreasingthe TI according to any other scheme, e.g., follows:

TI _(i+1)=max(Nmin,TI _(i)/2)  (5)

In some demonstrative embodiments, wireless communication unit 110 mayincrease the selected transmission interval, e.g., if device 102 is notable to transmit the discovery frame before the end of the discoverywindow.

In some demonstrative embodiments, wireless communication unit 110 mayincrease the TI by determining the next TI to be used for selecting thenext DW, e.g., as follows:

TI _(i+1)=min(2TI _(i) ,Nmax)  (6)

wherein Nmax denotes a predefined value. For example, Nmax may be amaximal frequency for the discovery frame transmission.

In another example, the successive TI may be determined by increasingthe TI according to any other scheme, e.g., follows:

TI _(i+1)=min(TI _(i)+1,Nmax)  (7)

Reference in now made to FIG. 2, which schematically illustrates adiscovery scheme including a plurality of discovery windows 210, 211,212, 213, 214, 215, 216, 217 and/or 218, in accordance with somedemonstrative embodiments. For example, devices 102, 104, 106 and/or 108(FIG. 1) may be allowed to attempt transmitting discovery frames duringDWs 210, 211, 212, 213, 214, 215, 216, 217 and/or 218.

In some demonstrative embodiments, wireless communication unit 110(FIG. 1) may set a TI 201, for example, including two DWs, e.g., DW 210and DW 211.

In some demonstrative embodiments, wireless communication unit 110(FIG. 1) may select a DW within TI 201. For example, wirelesscommunication unit 110 may select DW 210, e.g., if n=0.

In some demonstrative embodiments, wireless communication unit 110(FIG. 1) may schedule a transmission of the discovery frame during theselected DW 210.

In some demonstrative embodiments, device 102 (FIG. 1) may attempt totransmit the discovery frame within the selected DW 210.

In some demonstrative embodiments, wireless communication unit 110(FIG. 1) may adjust the transmission interval, e.g., based on whether ornot wireless communication medium 103 (FIG. 1) is observed to be busyduring a predefined time period of discovery window 210.

In some demonstrative embodiments, wireless communication unit 110(FIG. 1) may set a TI 202 successive to TI 201, e.g., based on whetheror not device 102 (FIG. 1) is able to transmit the discovery frameduring the predefined time period in DW 210.

In some demonstrative embodiments, TI 202 may be longer than TI 201,e.g., if device 102 (FIG. 1) is unable to transmit the discovery frameduring the time period T within DW 210. For example, TI 202 may includefour DWs, e.g., DWs 212, 213, 214 and/or 215. For example, wirelesscommunication unit 110 (FIG. 1) may determine TI 202 according toEquation 2, e.g., if a=2.

In some demonstrative embodiments, wireless communication unit 110(FIG. 1) may select a DW within TI 202. For example, wirelesscommunication unit 110 may select DW 215, e.g., if n=3.

In some demonstrative embodiments, wireless communication unit 110(FIG. 1) may schedule a transmission of the discovery frame during theselected DW 215.

In some demonstrative embodiments, device 102 (FIG. 1) may attempt totransmit the discovery frame within the selected DW 215.

In some demonstrative embodiments, wireless communication unit 110(FIG. 1) may adjust the transmission interval based on whether or notwireless communication medium 103 (FIG. 1) is observed to be busy duringa predefined time period of discovery window 215.

In some demonstrative embodiments, wireless communication unit 110(FIG. 1) may set a TI 203 successive to TI 202, e.g., based on whetheror not device 102 (FIG. 1) is able to transmit the discovery frameduring the predefined time period in DW 215.

In some demonstrative embodiments, TI 203 may be shorter than TI 202,e.g., if device 102 (FIG. 1) is able to transmit the discovery frameduring DW 215. For example, TI 203 may include three DWs, e.g., DWs 216,217 and/or 218. For example, wireless communication unit 110 (FIG. 1)may determine TI 203 according to Equation 3, e.g., if b=1.

Reference is made to FIG. 3, which schematically illustrates a method ofadjusting transmission intervals for discovery frames, in accordancewith some demonstrative embodiments. For example, one or more of theoperations of the method of FIG. 3 may be performed by a wirelesscommunication system, e.g., system 100 (FIG. 1); a wirelesscommunication device, e.g., devices 102, 104, 106 and/or 108 (FIG. 1);and/or a wireless communication unit, e.g., wireless communication units110 and/or 120 (FIG. 1).

As indicated at block 302, the method may include communicating over awireless communication medium according to a discovery scheme includinga plurality of discovery windows. For example, wireless communicationunit 110 (FIG. 1) may communicate over wireless communication medium 103(FIG. 1) according to discovery scheme 200 (FIG. 2), e.g., as describedabove.

As indicated at block 304, the method may include selecting a DWaccording to a TI. For example, wireless communication unit 110 mayselect DW 210 (FIG. 2), according to TI 201 (FIG. 2), e.g., as describedabove.

As indicated at block 306, the method may include scheduling thetransmission of the discovery frame for the selected DW. For example,wireless communication unit 110 (FIG. 1) may schedule the transmissionof the discovery frame for DW 210 (FIG. 2), e.g., as described above.

As indicated at block 308, the method may include adjusting thetransmission interval based on whether or not the wireless communicationmedium is observed to be busy during the predefined time period of theDW. For example, wireless communication unit 110 (FIG. 1) may adjust theTI based on whether or not wireless communication medium 103 (FIG. 1) isbusy.

As indicated at block 310, the method may include increasing thetransmission interval, e.g., if the wireless communication medium isobserved to be busy during the predefined time period of the DW. Forexample, wireless communication medium 110 (FIG. 1) may increase the TI,e.g., according to Equation 2, 6 or 7.

As indicated at block 312, the method may include decreasing thetransmission interval, e.g., if the wireless communication medium isobserved not to be busy during the predefined time period of the DW. Forexample, wireless communication medium 110 (FIG. 1) may decrease the TI,e.g., according to Equation 3, 4 or 5.

Reference is made to FIG. 4, which schematically illustrates a productof manufacture 400, in accordance with some demonstrative embodiments.Product 400 may include a non-transitory machine-readable storage medium402 to store logic 404, which may be used, for example, to perform atleast part of the functionality of device 102 (FIG. 1), device 104 (FIG.1), device 106 (FIG. 1), device 108 (FIG. 1), wireless communicationunit 110 (FIG. 1), wireless communication unit 120 (FIG. 1) and/or toperform one or more operations of the method of FIG. 3. The phrase“non-transitory machine-readable medium” is directed to include allcomputer-readable media, with the sole exception being a transitorypropagating signal.

In some demonstrative embodiments, product 400 and/or machine-readablestorage medium 402 may include one or more types of computer-readablestorage media capable of storing data, including volatile memory,non-volatile memory, removable or non-removable memory, erasable ornon-erasable memory, writeable or re-writeable memory, and the like. Forexample, machine-readable storage medium 402 may include, RAM, DRAM,Double-Data-Rate DRAM (DDR-DRAM), SDRAM, static RAM (SRAM), ROM,programmable ROM (PROM), erasable programmable ROM (EPROM), electricallyerasable programmable ROM (EEPROM), Compact Disk ROM (CD-ROM), CompactDisk Recordable (CD-R), Compact Disk Rewriteable (CD-RW), flash memory(e.g., NOR or NAND flash memory), content addressable memory (CAM),polymer memory, phase-change memory, ferroelectric memory,silicon-oxide-nitride-oxide-silicon (SONOS) memory, a disk, a floppydisk, a hard drive, an optical disk, a magnetic disk, a card, a magneticcard, an optical card, a tape, a cassette, and the like. Thecomputer-readable storage media may include any suitable media involvedwith downloading or transferring a computer program from a remotecomputer to a requesting computer carried by data signals embodied in acarrier wave or other propagation medium through a communication link,e.g., a modem, radio or network connection.

In some demonstrative embodiments, logic 404 may include instructions,data, and/or code, which, if executed by a machine, may cause themachine to perform a method, process and/or operations as describedherein. The machine may include, for example, any suitable processingplatform, computing platform, computing device, processing device,computing system, processing system, computer, processor, or the like,and may be implemented using any suitable combination of hardware,software, firmware, and the like.

In some demonstrative embodiments, logic 404 may include, or may beimplemented as, software, a software module, an application, a program,a subroutine, instructions, an instruction set, computing code, words,values, symbols, and the like. The instructions may include any suitabletype of code, such as source code, compiled code, interpreted code,executable code, static code, dynamic code, and the like. Theinstructions may be implemented according to a predefined computerlanguage, manner or syntax, for instructing a processor to perform acertain function. The instructions may be implemented using any suitablehigh-level, low-level, object-oriented, visual, compiled and/orinterpreted programming language, such as C, C++, Java, BASIC, Matlab,Pascal, Visual BASIC, assembly language, machine code, and the like.

EXAMPLES

The following examples pertain to further embodiments.

Example 1 includes an apparatus of wireless communication, the apparatuscomprising a wireless communication unit to communicate over a wirelesscommunication medium according to a discovery scheme including aplurality of contention-based discovery windows, the wirelesscommunication unit is to select a discovery window according to atransmission interval, to schedule transmission of a discovery frame forthe discovery window, and to adjust the transmission interval based onwhether or not the wireless communication medium is observed to be busyduring a predefined time period of the discovery window.

Example 2 includes the subject matter of Example 1 and optionally,wherein based on the transmission interval, the wireless communicationunit is to determine a number of discovery windows between successiveattempts to transmit the discovery frame, and to select the discoverywindow according to the number of discovery windows.

Example 3 includes the subject matter of Example 2 and optionally,wherein the wireless communication unit is to select the number ofdiscovery windows between a minimal transmission interval and thetransmission interval.

Example 4 includes the subject matter of Example 3 and optionally,wherein the wireless communication unit is to select a number, denotedn, between the minimal transmission interval and the transmissioninterval, and to schedule transmission of the discovery frame during ann-th discovery window, wherein n=0 is a current discovery window.

Example 5 includes the subject matter of any one of Examples 1-4 andoptionally, wherein the wireless communication unit is to increase thetransmission interval if the medium is observed to be busy during thepredefined time period.

Example 6 includes the subject matter of Example 5 and optionally,wherein the wireless communication unit is to increase the transmissioninterval from a first value, denoted TW, to a second value, TW+a,wherein a denotes a predefined value.

Example 7 includes the subject matter of any one of Examples 1-6 andoptionally, wherein the wireless communication unit is to decrease thetransmission interval if the medium is observed not to be busy duringthe predefined time period.

Example 8 includes the subject matter of Example 7 and optionally,wherein the wireless communication unit is to decrease the transmissioninterval from a first value, denoted TW, to a second value, the secondvalue is a greatest of a minimal transmission interval, denoted TWmin,and a difference (TW−b), wherein b denotes a predefined value.

Example 9 includes the subject matter of any one of Examples 1-8 andoptionally, wherein the predefined time period comprises a time periodbeginning at a start time of the discovery window and ending within thediscovery window.

Example 10 includes the subject matter of any one of Examples 1-8 andoptionally, wherein the predefined time period comprises an entirety ofthe discovery window.

Example 11 includes the subject matter of any one of Examples 1-10 andoptionally, wherein the transmission interval comprises a ServiceDiscovery frame transmission window (TW).

Example 12 includes the subject matter of any one of Examples 1-11 andoptionally, wherein the wireless communication medium comprises awireless communication channel over a 2.4 Gigahertz (GHz) frequency bandor a 5 GHz frequency band.

Example 13 includes the subject matter of any one of Examples 1-12 andoptionally, wherein the wireless communication unit is to perform thefunctionality of a Neighbor Awareness Networking (NAN) device todiscover other NAN devices according to the discovery scheme.

Example 14 includes a system of wireless communication, the systemcomprising a wireless communication device including at least oneantenna to communicate over a wireless communication medium; and awireless communication unit to communicate over the wirelesscommunication medium according to a discovery scheme including aplurality of contention-based discovery windows, the wirelesscommunication unit is to select a discovery window within a transmissioninterval, to schedule transmission of a discovery frame within thediscovery window, and to adjust the transmission interval based onwhether or not the medium is observed to be busy during a predefinedtime period of the discovery window.

Example 15 includes the subject matter of Example 14 and optionally,wherein based on the transmission interval, the wireless communicationunit is to determine a number of discovery windows between successiveattempts to transmit the discovery frame, and to select the discoverywindow according to the number of discovery windows.

Example 16 includes the subject matter of Example 15 and optionally,wherein the wireless communication unit is to select the number ofdiscovery windows between a minimal transmission interval and thetransmission interval.

Example 17 includes the subject matter of Example 16 and optionally,wherein the wireless communication unit is to select a number, denotedn, between the minimal transmission interval and the transmissioninterval, and to schedule transmission of the discovery frame during ann-th discovery window, wherein n=0 is a current discovery window.

Example 18 includes the subject matter of any one of Examples 14-17 andoptionally, wherein the wireless communication unit is to increase thetransmission interval if the medium is observed to be busy during thepredefined time period.

Example 19 includes the subject matter of Example 18 and optionally,wherein the wireless communication unit is to increase the transmissioninterval from a first value, denoted TW, to a second value, TW+a,wherein a denotes a predefined value.

Example 20 includes the subject matter of any one of Examples 14-19 andoptionally, wherein the wireless communication unit is to decrease thetransmission interval if the medium is observed not to be busy duringthe predefined time period.

Example 21 includes the subject matter of Example 20 and optionally,wherein the wireless communication unit is to decrease the transmissioninterval from a first value, denoted TW, to a second value, the secondvalue is a greatest of a minimal transmission interval, denoted TWmin,and a difference (TW−b), wherein b denotes a predefined value.

Example 22 includes the subject matter of any one of Examples 14-21 andoptionally, wherein the predefined time period comprises a time periodbeginning at a start time of the discovery window and ending within thediscovery window.

Example 23 includes the subject matter of any one of Examples 14-21 andoptionally, wherein the predefined time period comprises an entirety ofthe discovery window.

Example 24 includes the subject matter of any one of Examples 14-23 andoptionally, wherein the transmission interval comprises a ServiceDiscovery frame transmission window (TW).

Example 25 includes the subject matter of any one of Examples 14-24 andoptionally, wherein the wireless communication medium comprises awireless communication channel over a 2.4 Gigahertz (GHz) frequency bandor a 5 GHz frequency band.

Example 26 includes the subject matter of any one of Examples 14-25 andoptionally, wherein the wireless communication unit is to perform thefunctionality of a Neighbor Awareness Networking (NAN) device todiscover other NAN devices according to the discovery scheme.

Example 27 includes a method of wireless communication, the methodcomprising selecting a discovery window from a plurality ofcontention-based discovery windows according to a transmission interval;scheduling for the discovery window transmission of a discovery frameover a wireless communication medium; attempting to transmit thediscovery frame during the discovery window; and adjusting thetransmission interval based on whether or not the wireless communicationmedium is observed to be busy during a predefined time period of thediscovery window.

Example 28 includes the subject matter of Example 27 and optionally,comprising, based on the transmission interval, determining a number ofdiscovery windows between successive attempts to transmit the discoveryframe, and selecting the discovery window according to the number ofdiscovery windows.

Example 29 includes the subject matter of Example 28 and optionally,comprising selecting the number of discovery windows between a minimaltransmission interval and the transmission interval.

Example 30 includes the subject matter of Example 29 and optionally,comprising selecting a number, denoted n, between the minimaltransmission interval and the transmission interval, and schedulingtransmission of the discovery frame during an n-th discovery window,wherein n=0 is a current discovery window.

Example 31 includes the subject matter of any one of Examples 27-30 andoptionally, comprising increasing the transmission interval if themedium is observed to be busy during the predefined time period.

Example 32 includes the subject matter of Example 31 and optionally,comprising increasing the transmission interval from a first value,denoted TW, to a second value, TW+a, wherein a denotes a predefinedvalue.

Example 33 includes the subject matter of any one of Examples 27-32 andoptionally, comprising decreasing the transmission interval if themedium is observed not to be busy during the predefined time period.

Example 34 includes the subject matter of Example 33 and optionally,comprising decreasing the transmission interval from a first value,denoted TW, to a second value, the second value is a greatest of aminimal transmission interval, denoted TWmin, and a difference (TW−b),wherein b denotes a predefined value.

Example 35 includes the subject matter of any one of Examples 27-34 andoptionally, wherein the predefined time period comprises a time periodbeginning at a start time of the discovery window and ending within thediscovery window.

Example 36 includes the subject matter of any one of Examples 27-34 andoptionally, wherein the predefined time period comprises an entirety ofthe discovery window.

Example 37 includes the subject matter of any one of Examples 27-36 andoptionally, wherein the transmission interval comprises a ServiceDiscovery frame transmission window (TW).

Example 38 includes the subject matter of any one of Examples 27-37 andoptionally, wherein the wireless communication medium comprises awireless communication channel over a 2.4 Gigahertz (GHz) frequency bandor a 5 GHz frequency band.

Example 39 includes the subject matter of any one of Examples 27-38 andoptionally, comprising performing the functionality of a NeighborAwareness Networking (NAN) device to discover other NAN devicesaccording to the discovery scheme.

Example 40 includes a product including a non-transitory storage mediumhaving stored thereon instructions that, when executed by a machine,result in selecting a discovery window from a plurality ofcontention-based discovery windows according to a transmission interval;scheduling for the discovery window transmission of a discovery frameover a wireless communication medium; attempting to transmit thediscovery frame during the discovery window; and adjusting thetransmission interval based on whether or not the wireless communicationmedium is observed to be busy during a predefined time period of thediscovery window.

Example 41 includes the subject matter of Example 40 and optionally,wherein the instructions result in determining, based on thetransmission interval, a number of discovery windows between successiveattempts to transmit the discovery frame, and selecting the discoverywindow according to the number of discovery windows.

Example 42 includes the subject matter of Example 41 and optionally,wherein the instructions result in selecting the number of discoverywindows between a minimal transmission interval and the transmissioninterval.

Example 43 includes the subject matter of Example 42 and optionally,wherein the instructions result in selecting a number, denoted n,between the minimal transmission interval and the transmission interval,and scheduling transmission of the discovery frame during an n-thdiscovery window, wherein n=0 is a current discovery window.

Example 44 includes the subject matter of any one of Examples 40-43 andoptionally, wherein the instructions result in increasing thetransmission interval if the medium is observed to be busy during thepredefined time period.

Example 45 includes the subject matter of Example 44 and optionally,wherein the instructions result in increasing the transmission intervalfrom a first value, denoted TW, to a second value, TW+a, wherein adenotes a predefined value.

Example 46 includes the subject matter of any one of Examples 40-45 andoptionally, wherein the instructions result in decreasing thetransmission interval if the medium is observed not to be busy duringthe predefined time period.

Example 47 includes the subject matter of Example 46 and optionally,wherein the instructions result in decreasing the transmission intervalfrom a first value, denoted TW, to a second value, the second value is agreatest of a minimal transmission interval, denoted TWmin, and adifference (TW−b), wherein b denotes a predefined value.

Example 48 includes the subject matter of any one of Examples 40-47 andoptionally, wherein the predefined time period comprises a time periodbeginning at a start time of the discovery window and ending within thediscovery window.

Example 49 includes the subject matter of any one of Examples 40-47 andoptionally, wherein the predefined time period comprises an entirety ofthe discovery window.

Example 50 includes the subject matter of any one of Examples 40-49 andoptionally, wherein the transmission interval comprises a ServiceDiscovery frame transmission window (TW).

Example 51 includes the subject matter of any one of Examples 40-50 andoptionally, wherein the wireless communication medium comprises awireless communication channel over a 2.4 Gigahertz (GHz) frequency bandor a 5 GHz frequency band.

Example 52 includes the subject matter of any one of Examples 40-51 andoptionally, wherein the instructions result in performing thefunctionality of a Neighbor Awareness Networking (NAN) device todiscover other NAN devices according to the discovery scheme.

Example 53 includes an apparatus of wireless communication, theapparatus comprising means for selecting a discovery window from aplurality of contention-based discovery windows according to atransmission interval; means for scheduling for the discovery windowtransmission of a discovery frame over a wireless communication medium;means for attempting to transmit the discovery frame during thediscovery window; and means for adjusting the transmission intervalbased on whether or not the wireless communication medium is observed tobe busy during a predefined time period of the discovery window.

Example 54 includes the subject matter of Example 53 and optionally,comprising means for determining, based on the transmission interval, anumber of discovery windows between successive attempts to transmit thediscovery frame, and selecting the discovery window according to thenumber of discovery windows.

Example 55 includes the subject matter of Example 54 and optionally,comprising means for selecting the number of discovery windows between aminimal transmission interval and the transmission interval.

Example 56 includes the subject matter of Example 55 and optionally,comprising means for selecting a number, denoted n, between the minimaltransmission interval and the transmission interval, and schedulingtransmission of the discovery frame during an n-th discovery window,wherein n=0 is a current discovery window.

Example 57 includes the subject matter of any one of Examples 53-56 andoptionally, comprising means for increasing the transmission interval ifthe medium is observed to be busy during the predefined time period.

Example 58 includes the subject matter of Example 57 and optionally,comprising means for increasing the transmission interval from a firstvalue, denoted TW, to a second value, TW+a, wherein a denotes apredefined value.

Example 59 includes the subject matter of any one of Examples 53-58 andoptionally, comprising means for decreasing the transmission interval ifthe medium is observed not to be busy during the predefined time period.

Example 60 includes the subject matter of Example 59 and optionally,comprising means for decreasing the transmission interval from a firstvalue, denoted TW, to a second value, the second value is a greatest ofa minimal transmission interval, denoted TWmin, and a difference (TW−b),wherein b denotes a predefined value.

Example 61 includes the subject matter of any one of Examples 53-60 andoptionally, wherein the predefined time period comprises a time periodbeginning at a start time of the discovery window and ending within thediscovery window.

Example 62 includes the subject matter of any one of Examples 53-60 andoptionally, wherein the predefined time period comprises an entirety ofthe discovery window.

Example 63 includes the subject matter of any one of Examples 53-62 andoptionally, wherein the transmission interval comprises a ServiceDiscovery frame transmission window (TW).

Example 64 includes the subject matter of any one of Examples 53-63 andoptionally, wherein the wireless communication medium comprises awireless communication channel over a 2.4 Gigahertz (GHz) frequency bandor a 5 GHz frequency band.

Example 65 includes the subject matter of any one of Examples 53-64 andoptionally, comprising means for performing the functionality of aNeighbor Awareness Networking (NAN) device to discover other NAN devicesaccording to the discovery scheme.

Functions, operations, components and/or features described herein withreference to one or more embodiments, may be combined with, or may beutilized in combination with, one or more other functions, operations,components and/or features described herein with reference to one ormore other embodiments, or vice versa.

While certain features of the invention have been illustrated anddescribed herein, many modifications, substitutions, changes, andequivalents may occur to those skilled in the art. It is, therefore, tobe understood that the appended claims are intended to cover all suchmodifications and changes as fall within the true spirit of theinvention.

What is claimed is:
 1. An apparatus comprising: a wireless communicationunit to communicate over a wireless communication medium according to adiscovery scheme including a plurality of contention-based discoverywindows, said wireless communication unit is to select a discoverywindow according to a transmission interval, to schedule transmission ofa discovery frame for said discovery window, and to adjust saidtransmission interval based on whether or not said wirelesscommunication medium is observed to be busy during a predefined timeperiod of said discovery window.
 2. The apparatus of claim 1, wherein,based on said transmission interval, said wireless communication unit isto determine a number of discovery windows between successive attemptsto transmit said discovery frame, and to select said discovery windowaccording to said number of discovery windows.
 3. The apparatus of claim2, wherein said wireless communication unit is to select said number ofdiscovery windows between a minimal transmission interval and saidtransmission interval.
 4. The apparatus of claim 3, wherein saidwireless communication unit is to select a number, denoted n, betweensaid minimal transmission interval and said transmission interval, andto schedule transmission of said discovery frame during an n-thdiscovery window, wherein n=0 is a current discovery window.
 5. Theapparatus of claim 1, wherein said wireless communication unit is toincrease said transmission interval if said medium is observed to bebusy during said predefined time period.
 6. The apparatus of claim 5,wherein said wireless communication unit is to increase saidtransmission interval from a first value, denoted TW, to a second value,TW+a, wherein a denotes a predefined value.
 7. The apparatus of claim 1,wherein said wireless communication unit is to decrease saidtransmission interval if said medium is observed not to be busy duringsaid predefined time period.
 8. The apparatus of claim 7, wherein saidwireless communication unit is to decrease said transmission intervalfrom a first value, denoted TW, to a second value, said second value isa greatest of a minimal transmission interval, denoted TWmin, and adifference (TW−b), wherein b denotes a predefined value.
 9. Theapparatus of claim 1, wherein said predefined time period comprises atime period beginning at a start time of said discovery window andending within said discovery window.
 10. The apparatus of claim 1,wherein said predefined time period comprises an entirety of saiddiscovery window.
 11. The apparatus of claim 1, wherein saidtransmission interval comprises a Service Discovery frame transmissionwindow (TW).
 12. The apparatus of claim 1, wherein said wirelesscommunication medium comprises a wireless communication channel over a2.4 Gigahertz (GHz) frequency band or a 5 GHz frequency band.
 13. Theapparatus of claim 1, wherein said wireless communication unit is toperform the functionality of a Neighbor Awareness Networking (NAN)device to discover other NAN devices according to said discovery scheme.14. A system comprising: a wireless communication device including: atleast one antenna to communicate over a wireless communication medium;and a wireless communication unit to communicate over said wirelesscommunication medium according to a discovery scheme including aplurality of contention-based discovery windows, said wirelesscommunication unit is to select a discovery window within a transmissioninterval, to schedule transmission of a discovery frame within saiddiscovery window, and to adjust said transmission interval based onwhether or not said medium is observed to be busy during a predefinedtime period of said discovery window.
 15. The system of claim 14,wherein, based on said transmission interval, said wirelesscommunication unit is to determine a number of discovery windows betweensuccessive attempts to transmit said discovery frame, and to select saiddiscovery window according to said number of discovery windows.
 16. Thesystem of claim 15, wherein said wireless communication unit is toselect said number of discovery windows between a minimal transmissioninterval and said transmission interval.
 17. The system of claim 14,wherein said wireless communication unit is to increase saidtransmission interval if said medium is observed to be busy during saidpredefined time period.
 18. The system of claim 14, wherein saidwireless communication unit is to decrease said transmission interval ifsaid medium is observed not to be busy during said predefined timeperiod.
 19. The system of claim 14, wherein said predefined time periodcomprises a time period beginning at a start time of said discoverywindow and ending within said discovery window.
 20. A method comprising:selecting a discovery window from a plurality of contention-baseddiscovery windows according to a transmission interval; scheduling forsaid discovery window transmission of a discovery frame over a wirelesscommunication medium; attempting to transmit said discovery frame duringsaid discovery window; and adjusting said transmission interval based onwhether or not said wireless communication medium is observed to be busyduring a predefined time period of said discovery window.
 21. The methodof claim 20 comprising, based on said transmission interval, determininga number of discovery windows between successive attempts to transmitsaid discovery frame, and selecting said discovery window according tosaid number of discovery windows.
 22. The method of claim 20, whereinsaid predefined time period comprises a time period beginning at a starttime of said discovery window and ending within said discovery window.23. A product including a non-transitory storage medium having storedthereon instructions that, when executed by a machine, result in:selecting a discovery window from a plurality of contention-baseddiscovery windows according to a transmission interval; scheduling forsaid discovery window transmission of a discovery frame over a wirelesscommunication medium; attempting to transmit said discovery frame duringsaid discovery window; and adjusting said transmission interval based onwhether or not said wireless communication medium is observed to be busyduring a predefined time period of said discovery window.
 24. Theproduct of claim 23, wherein said instructions result in determining,based on said transmission interval, a number of discovery windowsbetween successive attempts to transmit said discovery frame, andselecting said discovery window according to said number of discoverywindows.
 25. The product of claim 24, wherein said instructions resultin selecting said number of discovery windows between a minimaltransmission interval and said transmission interval.
 26. The product ofclaim 25, wherein said instructions result in selecting a number,denoted n, between said minimal transmission interval and saidtransmission interval, and scheduling transmission of said discoveryframe during an n-th discovery window, wherein n=0 is a currentdiscovery window.
 27. The product of claim 23, wherein said instructionsresult in increasing said transmission interval if said medium isobserved to be busy during said predefined time period.
 28. The productof claim 27, wherein said instructions result in increasing saidtransmission interval from a first value, denoted TW, to a second value,TW+a, wherein a denotes a predefined value.
 29. The product of claim 23,wherein said instructions result in decreasing said transmissioninterval if said medium is observed not to be busy during saidpredefined time period.
 30. The product of claim 29, wherein saidinstructions result in decreasing said transmission interval from afirst value, denoted TW, to a second value, said second value is agreatest of a minimal transmission interval, denoted TWmin, and adifference (TW−b), wherein b denotes a predefined value.